The field of this invention relates to hydrocolloid injection systems for manufacturing and using of a reversible hydrocolloid dental impression material.
The use of a reversible hydrocolloid impression material is quite common within the dental field. Such material is used for taking dental impressions for the subsequent construction of inlay, fixed bridge and partial denture. The reversible hydrocolloid impression material is dispensed in liquid form onto the specific dental area at which it is to be desired to make the impression. Within a short period of time the material hardens into a solid. The impression material is then removed and the resulting formed mold is then utilized in the construction of the inlays, bridges or dentures.
The reversible hydrocolloid impression material which is used in dental work is usually comprised of a formulated aqueous suspension of a gum (such as agar agar). This material is a gel (solid) at ordinary temperatures such as 75.degree. to 100.degree. F. If the material is heated to approximately 200.degree. to 212.degree. F., the material becomes liquid and readily flowable. Therefore, the user of the material can inject the material in liquid form to the desired location. Upon the liquid cooling, it will assume the configuration of its environment. Therefore, such material is of significant advantage with taking of a dental impression.
It is necessary to use a tool to cause the liquid impression material to be deposited at confined quartered locations. A desirable type of such a tool has been found to be a syringe. The hydrocolloid material is preformed into the shape of a stick. The stick hydrocolloid material is inserted within the syringe prior to usage. The entire syringe is then immersed in boiling water for a few minutes, until the material becomes liquid form. The syringe is then removed from the boiling water, cooled to a comfortable usable temperature (approximately 150.degree. F.), and is then used by the user to dispense the hydrocolloid material at the desired location. All known prior art systems utilize some form of syringe mechanism, which is then loaded with some form of hydrocolloid material in stick form. The syringe is reusable.
There is also known to use a hydrocolloid filled cartridge in conjuction with an applying tool. Such a cartridge is shown in U.S. Pat. No. 3,731,453, issued to Don D. Porteous. The disadvantages of the cartridge system are: (1) By using a separate dispensing tool with the warmed cartridge, working time is severely limited due to cooling of the cartridge before it can be dispensed; (2) It requires the user to physically load the cartridge into the tool.
The disadvantages of such prior art hydrocolloid injection systems are that the syringe must be cleaned between times of usage. This cleaning is normally time consuming, and if the syringe is not cleaned properly, the syringe may be difficult to use at the next usage. Also, periodic maintenance of reusable parts of the syringe is required. Further, this prior hydrocolloid injection system required a supply of hydrocolloid injection sticks and these sticks must be contained within an airtight container to prevent the sticks from drying out. Still further, in loading the syringe, air may be entrapped, which during boiling can expand and discharge the syringe plunger ruining the hydrocolloid material. Additionally, entrapped air during dispensing will ruin the impression.
It would be desirable to utilize a hydrocolloid injection system wherein the hydrocolloid material is preloaded within each individual dispensing mechanism and, upon the hydrocolloid material having been dispensed, the dispensing mechanism can be merely discarded. Utilizing of the dispensing mechanism as also the storage container eliminates the need and expense of such storage containers, as well as eliminates the need to load the dispensing mechanism. Also, it would be desirable to design the dispensing mechanism to be inexpensive to manufacture and therefore, inexpensive to use, even though the dispensing mechanism is just discarded after a single use.